Currently, semiconductor die are initially tested while part of a wafer. That is, a wafer is placed in a machine known as a wafer prober and an apparatus known as a probe card is brought into contact with some or all of the semiconductor die on the wafer. The probe card has arrays of probes on it that, via an optical measurement and adjustment process, are typically aligned to the complimentary bond or probe pads on the semiconductor die. Since the wafer and probe card are each a monolithic structure, the probe card is typically fixed in place while the wafer is mechanically moved into alignment with the probes on the probe card.
A probe card typically comprises a probe head coupled to a printed circuit board. The probe head carries the probes that actually touch down on a wafer. The printed circuit board facilitates connecting the electrical contacts of the probe head to a place of access by external automated test equipment (ATE).